White Clover Silage

Grass-only swards need synthetic nitrogen to thrive.
White clover fixes its own nitrogen, cutting fertiliser use and lowering emissions.

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The Climate Issue

In most dairy systems, grass grows fast, but not on its own. To stay productive, it needs nitrogen fertiliser. That means more spreading, more emissions, and more cost.

Nitrogen from synthetic fertilisers contributes to ammonia, nitrate leaching, and nitrous oxide, one of the most potent greenhouse gases. Every extra kilo applied can push emissions higher, especially if not well timed or absorbed.

Grass-only swards, while common, can’t fix nitrogen from the air. They rely entirely on inputs. That’s where clover comes in.

The Solution: White Clover

White clover is a small legume that lives happily alongside ryegrass. It pulls nitrogen straight from the air and shares it with surrounding plants, naturally fertilising the soil.

When sown into pastures, clover boosts total protein in the sward, improves digestibility, and reduces the need for chemical fertilisers. Trials show that pastures with 20-30 % white clover can cut fertiliser use by up to 100 kg N/ha without loss of yield.

It’s also rich in energy, supports strong milk solids, and grows well through summer when ryegrass can struggle.

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Key Benefits when sowing White Clover

Cut Emissions

Less fertiliser means fewer emissions. Clover-based swards reduce both direct N₂O emissions and indirect ammonia losses from spreading.

Save on Fertiliser

Replacing 100 kg of synthetic nitrogen saves up to €90/ha. These savings repeat every year once clover is established and managed correctly.

Animal Performance

Clover has higher digestibility and protein content than ryegrass alone. That supports milk solids and improves feed intake in grazing herds.

Impact of sowing White Clover

Sowing white clover is a smart, soil-based way to reduce fertiliser needs and cut emissions. Once sown and managed well, it delivers both economic and environmental results.

Teagasc trials and farm case studies show white clover can:

Cut synthetic nitrogen use by 80–100 kg/ha
Lower GHG emissions by 5–8 %
Improve milk solids per hectare
Save €80–€100/ha in fertiliser costs

See the example below for how adoption affects performance on a 50-hectare grazing platform.

Scenario	Clover in Sward %	Fertiliser Savings / 50 ha	GHG Emissions	% GHG Reduction
0% of platform	0%	-	0.960 kg CO₂-eq/kg milk	0% kg CO₂-eq/kg milk
50% of platform	20-25%	€2,250	0.918 kg CO₂-eq/kg milk	4.4% kg CO₂-eq/kg milk
100% of platform	25-30%	€4,500	0.885 kg CO₂-eq/kg milk	7.8% kg CO₂-eq/kg milk

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Considerations

Establishing

Clover needs time and care to establish. Overseeding works well on existing swards but needs good soil fertility, light grazing, and no clover-suppressing sprays.

Grazing Practice

Frequent, light grazing helps clover persist. Heavy covers or long intervals between grazing can reduce clover content over time.

Nutrient Balance

Clover reduces the need for nitrogen but doesn’t supply phosphorus or potassium. Balanced fertiliser planning is still essential to minimize health complications through bloating.

Implementation

Switching to clover-based pastures is low-cost and low-risk. With the right steps, most dairy farms can see gains in 12–18 months. Here’s how to begin:

Test and prepare soils. Ensure good pH (6.3+), P and K indexes. Lime and correct nutrient imbalances before seeding.
Overseed in spring or autumn. Choose a proven white clover variety. Graze tightly before sowing and again post-germination to reduce grass competition.
Adapt nitrogen plan. Cut synthetic N once clover is established-typically by 70-100 kg N/ha. Use protected urea where fertiliser is still needed.

Behind the Research

ODOS Tech was founded by Cian White and Alejandro Vergara, two sustainability specialists with deep expertise in agricultural climate action.

Cian, a researcher at Trinity College Dublin with a background in environmental science, works on restoring nature to increase biodiversity on farms by using satellite images to track trees, hedgerows, and other habitats. Alejandro, a PhD researcher at University College Dublin, helps farmers measure their carbon emissions footprint and implement mitigation strategies to reduce their impact.

Together, they helped lead the carbon and nature-based work for the Farm Zero C project at Shinagh Farm, one of Europe’s first net-zero dairy pilots. At ODOS, they build smart, science-based tools to help agri-food businesses protect the environment and restore nature.

Research

Teagasc Moorepark Clover Trials

Teagasc research over multiple years shows that white clover swards can match or exceed grass-only yields with 100 kg less nitrogen per hectare. Milk solids and pasture quality also improve.

Farm Zero C at Shinagh

Shinagh Farm added clover to key paddocks and reduced N input by 70 kg/ha without hurting yield. Summer pasture growth and milk performance remained strong.

EU Green Deal & CAP

White clover fits with climate and biodiversity goals under the EU Green Deal. CAP now supports its adoption as part of eco-scheme and nutrient management plans across member states.

Ready to reduce emissions through White Clover?

Talk to our Carbon Footprint & Biodiversity experts on how we can help.